Improvement in safety-valve



tnted Bintec S. B. DOUGHEBTY, OFSOUTH BERGEN, NEW JRSEY.

Letters Patent No. 91,725, dated .Tune 22, 1869.

IMPROVEMENT IN SAFETY-VALVE.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern Be it known that I, S. B. DOUGHERTY, of South Bergen, in the county of Hudson, and StateV of New Jersey, have invented a new and useful Improvement in Safety'Valves for locomotive-engines and other boilers, of which the following is a full, clear, and exact description, reference being had to the accompanyiulghdawing, forming part of this specification, and in w xc Figure l represents a sectional elevation of asafetyvalve constructed in accordance with my invention, and

Figure 2, a plan of the valve-box or seat-portion of the valve.

Similar letters of reference indicate corresponding parts. f v

My improvement has reference to that description of safety-valves in which a large'area of escape is provided for the steam undera small load or weight upon the valve, by giving to the valve a hollow form, so that when down on its seat or seats, it has an annular exposure to the steam, and when lifted, opens escape for the steam both through and around and outside. of it.

In safety-valves of this description, there has usually been great diiiculty in making the valve bear with uniformity on both of its seats so as to securea close fit of the valve when closed, by reason of the expansion and contraction which take place, under exposure to the steam, of the intermediate portion of the valve that connects the upper and lower bearing-surfaces of the valve, and which, being generally in the form of a long cylinder 0r tube, favors such objectionable expansion and contraction, and virtually makes of the two valve-bearing surfaces, two valves.

My iuvention'obviates these diculties, and includes atapering construction of the valve, so that its two bearin g-suriaces lie in the same conical igureor outline, and the seats on which the valve rests are similarly disposed, and in close relationship to each other, whereby not only are the disadvantages hereinbefore specified avoided, but increased facility is afforded for construction of the entire valve. v

IReferring to the accompanying drawing, the valvebox or seat is made up of inner 4and outer cylindrical portions A and B, both of which are open at their top, and the outer one, A, opens also below, but the inner one, B, closed at its bottom.

On the upper edge of these cylinders A and B, are l formed valve-seats c and 1) both of which are disposed to lie in the same conical outline or figure, so that on a straight-edge being applied to their faces, to connect them, the same will touch or lie on both faces. l

This construction, which also applies to the outer or bearing-surfaces of the valve C, largely facilitatesthe true turning and fitting of the valve and its seat or seats.

Such arrangement of the seats a and b, in fact, makes of them but one, and the valve-healing surfaces being in line, or extensions one of another, 'constitute but the one valve in the strictest sense of the term.

This valve C, which is of a hollow tapering form, is open above and below, and may be guided in its play by wings c c, arranged to project from a central tubu` lar portion, d, andv made to freely t the inner cylinder B.

The Vouter cylinder A may be joined to the inner one by means of radial connections e. r

lIt will be observedthat the valve C, when down, se-

cures an annular presentation of it to the steam, which is 4admitted from below between the twocylinders A without exposing the valve toauy undue or Vas they maybe termed.

When the valve is raised, escape for the surplus steam is provided, both through it and outside of or around it.

Either a spring, direct weight, or lever and weight, may be applied to keep the valve closed, and if a spring, it may either be applied in a direct manner, as represented in the drawing, or to act upon the valve through the intervention of a lever.

An upper. or outer case may be used, if desired, to give to the safety-valve a lock-up character.

What is here claimed, and desired to be secured by Letters Patent, is

rlhe hollow tapering valve C, having its outer bearing-surfaces in line, as described, in combination with the cylinders A and B, arranged as specified, and having the valve-seats a and b disposed to lie in the same conical line or tgure,substantial1y as herein set forth.v

S. B. DOUGHERTY.

Witnesses:

FRED, HAYNns, J. W. GOOMBs. 

